Is it possible to hack a facebook account?

[Eni]

So ok, i know that this question was asked so many times and most of the people will think is stupid but i really need to know my sisters facebook account pasword. I don't need it to do messy things with her life i just want to read the conversation between her and a boy i think she is dating. So that is not important, dont suggest me keylogging cause we are using different laptops and i dont have acces to hers. Please tell me is it possible.